An airbrush normally has mounted thereon a reservoir in which is held a quantity of paint to be fed to the airbrush. By the very nature of the paint, there is a tendency for the passage or passages in the reservoir through which the paint passes to become blocked with dried paint. In order that the cup can be used further, it is necessary for it to be cleaned out. As the dimensions of such cups and the passages therein are normally very small, such a cleaning process is time-consuming and not necessarily very efficient.
Furthermore, as the orientation of the airbrush, and hence of a reservoir which is attached thereto, varies from user to user or even whilst being used by one user, an outlet for paint in the reservoir may not always be at the lowest point. In the case where for example the paint is fed to the airbrush by suction, this could have the effect that air enters the suction line.